Redmine

Hi,
I've installed redmine following the guide in http://www.redmine.org/projects/redmine/wiki/HowTo_Install_Redmine_25x_on_Ubuntu_1404_with_Apache2_Phusion_Passenger_MySQL_and_Subversion and afterwards i've installed the plugin redmine_re.
When i try to access the summary of a requirement with a URL like /re_artifact_properties/2 an internal server error pops up with the following lines in the redmine's log:

ActionView::Template::Error (Permission denied - /usr/share/redmine/public/javascripts/.permissions_check.22638100.23720.347005):
    15:   <% end %>
    16:   <div class="average_rating">&oslash;&nbsp;<%= re_rating.re_artifact_properties.average_rating %></div>
    17: </div>
    18: <%= javascript_include_tag 'ratings.js', :plugin => 'redmine_re', :cache => true %>
  app/helpers/application_helper.rb:1253:in `javascript_include_tag'

I've come to the solution of changing the owner of the entire /usr/share/redmine installation with chown -R www-data:www-data but i wonder if there's a solution less drastic
Cheers